shock waves - 2024 ACF Winter at Northwestern

Question

The Rankine–Hugoniot (“RANK-in oo-gohn-YOH”) conditions relate the discontinuities in density, pressure, and flow velocity across these phenomena. For 10 points each:

[10m] A sonic boom is the sound that results from what phenomena?

ANSWER: shock waves [accept sonic boom or bow shock or oblique shock; prompt on waves]

[10e] Sonic booms occur when an object exceeds the speed of sound, meaning its value of this scientist’s namesake number is greater than one. That number named for this scientist equals an object’s speed over the speed of sound.

ANSWER: Ernst Mach [accept Mach number]

[10h] The thickness of shock waves will approximately equal this quantity, which is very large in materials exhibiting ballistic transport. The Knudsen number equals this quantity over the length scale.

ANSWER: mean free path [prompt on mfp or lambda]

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Summary


2024 ACF Winter at UC Berkeley	2024-11-16	Y	3	20.00	100%	33%	67%
2024 ACF Winter at Clemson	2024-11-16	Y	8	12.50	100%	25%	0%
2024 ACF Winter at Clemson	2024-11-16	Y	8	12.50	13%	13%	100%
2024 ACF Winter at Lehigh	2024-11-16	Y	9	13.33	100%	11%	22%
2024 ACF Winter at Northwestern	2024-11-16	Y	9	13.33	100%	33%	0%
2024 ACF Winter at Ohio State	2024-11-16	Y	7	11.43	100%	14%	0%
2024 ACF Winter at Online	2024-11-16	Y	9	10.00	100%	0%	0%
2024 ACF Winter at UBC	2024-11-16	Y	3	16.67	67%	67%	33%
2024 ACF Winter at Oxford	2024-11-16	Y	11	13.64	100%	36%	0%
2024 ACF Winter at Brandeis	2024-11-16	Y	10	11.00	100%	10%	0%

Data


UIUC D	Indiana B	0	10	10
Miami	Purdue D	0	10	10
WashU C	Notre Dame	0	10	10
Purdue A	UChicago C	10	10	20
UChicago A	Purdue B	10	10	20
WashU D	Purdue C	0	10	10
WashU B	UIUC A	10	10	20
UIUC B	Indiana A	0	10	10
SIUE A	UIUC C	0	10	10